THE STUDY OF SUBAERIAL AND SUBAQUEOUS SAND RIPPLES

The report contains a study of subaqueous ripples in the marine environment, but two desert field studies also were undertaken. A dip meter was constructed for measurement of ripple geometry on the sea floor. Because existing current meters are unable to distinguish or record a sudden current reversal, a simple surge meter was devised, constructed, and calibrated. Experimental sediment traps were installed at varying distances above the bottom to obtain an indication of suspended sediment distribution. A series of nine dives were made in the San Pedro Channel, California, during the portion of the subaqueous study covered by this report. All instruments that were developed were tested and in those cases where necessary, calibrated. Collection of data was accomplished on ripple type, ripple geometry, sediment character, surge direction, surge velocity, and the influence of obstructions. Two unique subaerial ripple types were observed at the Kelso Dunes, in the Mojave Desert, California: a mixed-form consisting of light and dark sand at the edge of a dune slip face, and an area of compound ripples that developed in a field of changing wind. (Author) See also semi-annual progress rept. dated 1 Jul 67, AD-681 046. Limited number of copies containing color other than black and white are available until stock is exhausted. Reproductions will be made in black and white only.